1. Field of the Invention
The present invention relates to an electrical distribution system for distributing electrical power, and, more particularly, to an electrical distribution system with remote monitoring and/or control of substations.
2. Description of the Related Art
An electrical distribution system typically includes a transmission circuit in the form of one or more transmission lines which carry high voltage electricity. A plurality of substations are connected with the transmission circuit and convert the high voltage electricity carried by the transmission circuit to lower voltage electricity which is transmitted over a distribution feeder circuit to the end users.
It is known to provide monitoring and control of substations using a Supervisory Control And Data Acquisition (SCADA) System. In general, a SCADA system includes a single control unit which monitors and controls operation of the number of substations in the electrical distribution system. Intelligent electronic devices (IED) such as a power outage monitor or automated meter transmit a signal via either hardwired or wireless communication links to the single control unit of the SCADA system. The single control unit can then determine whether a power outage condition has occurred, and control controllable devices within the substation accordingly. A problem with a SCADA system is that control only occurs through the single control unit and failure of the control unit renders the entire system inoperable.
It is also known to couple a SCADA system with a geographic information system (GIS) which provides information relating to specific types and placement locations of electronic devices within a geographic area. If the single control unit of the SCADA system determines that a power outage condition has occurred, the GIS data may be utilized by the SCADA control unit to determine the approximate location of a probable fault and/or to compile a list of electrical devices which may be needed to repair the fault.
It is additionally known to provide a customer information system (CIS) which receives information from the control unit of the SCADA system pertaining to, e.g., a possible outage area or location, and allows customers to access such information.
Although SCADA systems as described above are generally acceptable for monitoring and/or controlling electrical power within an electrical distribution system, they do have certain problems. For example, if the single control unit of the SCADA system becomes inoperable, monitoring and/or control of the substations within the electrical distribution system from a remote location is impossible. Additionally, if a power outage occurs within a distribution feeder circuit, an electrical device such as a fuse, breaker, etc. may be identified which caused the problem, but the exact operating conditions both before and after the power outage condition remain unknown. Moreover, traditional SCADA systems generally are reactive systems in that they determine that a power outage condition has already occurred. They do not proactively consider such factors as weather related factors which may affect the transmission capacity of a transmission line and/or distribution feeder circuit which could result in an overload condition and cause a power outage condition.
The present invention provides an electrical distribution system and corresponding method of distributing electrical power, wherein a plurality of substations include processing circuits which are connected to each other and to monitoring devices and intelligent electronic devices with an open architecture such that operation at any particular substation may be monitored and/or controlled at any substation within the electrical distribution system.
The invention comprises, in one form thereof, an electrical distribution system including a communications network; a transmission circuit; a plurality of distribution feeder circuits; at least one monitoring device; and a plurality of substations. Each monitoring device is associated with an operating parameter of the transmission circuit or one of the distribution feeder circuits. Each of the substations is electrically connected between the transmission circuit and at least one of the distribution feeder circuits. Each substation includes at least one controllable device and a control unit. The control unit at each substation includes a communications device and a processing circuit. The communications device is independently coupled with the communications network for providing data to and receiving data from the communications network. The processing circuit is coupled with the communications device and at least one monitoring device. The processing circuit at least intermittently receives an output signal from the monitoring device and at least intermittently transmits an output signal to the communications network via the communications device. The processing circuit is configured to control operation of at least one controllable device at the corresponding substation. Additionally, the processing circuit is configured to control operation of at least one controllable device at a remote substation.
An advantage of the present invention is that the control units at each substation are coupled with each other with an open architecture such that operation at any substation may be monitored and/or controlled at any other substation.
Another advantage is that operation of a particular distribution feeder circuit may be monitored and/or controlled at a remote substation, even if the local substation fails.
Yet another advantage is that the control unit may be coupled with a weather station to receive data corresponding to a transmission capacity of an associated distribution feeder circuit.
A still further advantage is that each of the control units may be coupled with a geographic information system which provides data pertinent to specific types of electronic devices within a corresponding geographic area and/or specific locations of electronic devices within the geographic area.
A still further advantage is that each control unit may be coupled with a customer information system allowing customers to directly access information pertaining to electrical power distribution in their area, such as the status of a power outage condition and/or rate information.
An additional advantage is that each control unit may be provided with a graphical user interface which graphically illustrates to a user certain parameters associated with the electrical distribution system, such as the location of a cause of a power outage condition; the location of at least one controllable device within a distribution feeder circuit; and/or a graphical illustration of specific electrical devices within a particular distribution feeder circuit and/or transmission circuit.